[ Figure 1.i.1 ] How Autonomic Dysreflexia Happens THE BODY’S RESPONSE TO PAIN Brain BEFORE SCI 1. Blood vessels constrict by reflex action in response to pain and raise your blood pressure. 2. Nerves send messages up to your brain through your spinal cord, and you feel the pain. 3. Your brain senses that the blood vessels are constricting and your blood pressure is too high. 4. Your brain sends a message down through the spinal cord to dilate [open up] your blood vessels, which lowers your blood pressure. Spinal cord pathway to tell blood vessels to dilate Nonspinal cord pathway to tell brain what blood vessels are doing Blood Vessels Pain in hip CONSTRICT [reflex] Brain AFTER SCI 1. Blood vessels constrict by reflex action in response to pain and raise your blood pressure [same as before SCI]. 2. You will most likely not feel the pain because the messages can’t pass through the injured spinal cord and up to your brain. 3. Your brain senses that the blood vessels are constricting and blood pressure is too high [same as before SCI]. 4. The area from T7 to T10 of the spinal cord sends messages to many of the blood vessels in your body. If your injury is at or above T6 level, your brain can’t get the dilation message back down to the blood vessels below your injury. Your blood pressure stays high because the shut-off valve to lower it doesn’t get the signal. Spinal cord pathway to tell blood vessels to dilate; but message can’t get past the level of injury Nonspinal cord pathway to tell brain what blood vessels are doing Level of spinal cord injury [T6-10] Blood Vessels Pain in hip CONSTRICT [reflex] becomes more intense [ 62 ] | Yes, You Can!